A Surprise for Evolution in Giant Tree of Life – “Researchers build the world’s largest evolutionary tree and conclude that species arise because of chance mutations — not natural selection…. This controversial proposal stems from efforts by Hedges and collaborators to build the world’s most comprehensive tree of life — a chart plotting the connections among 50,000 species of Earth’s vast menagerie. Their analysis suggests that speciation is essentially random. No matter what the life form — plant or animal, insect or mammal — it takes about 2 million years for a new species to form. Random genetic events, not natural selection, play the main role in speciation.” – see also Was Charles Darwin Wrong About Speciation? from razib.

Behavioral idiosyncrasy reveals genetic control of phenotypic variability [pdf] – “If we could rear genetically identical individuals from a variety of genetic backgrounds and rear them in the same environment, how much phenotypic variation between individuals of the same genotype would we see? Would different genetic backgrounds differ in their degree of variability? What would account for these differences? We used Drosophila inbred lines to address these questions focusing on variability in locomotor handedness. We show that different genotypes vary dramatically in their propensity for variability, that phenotypic variability itself, as a trait, can be heritable, and that loci affecting variability can be mapped. The genetic control of variability has received little attention in quantitative genetics despite the important role variability plays in explaining phenotypic variation between individuals.”

Ancient DNA Tells a New Human Story – “The study of ancient DNA has challenged this view. We now know that mass migrations occurred repeatedly, overwhelming natives while absorbing some of their genes…. Joseph Pickrell of Columbia University and David Reich of Harvard University argue that ‘major upheavals’ of human population have been ‘overwriting’ the genetic history of the past 50,000 years. The result, they say, is that ‘present-day inhabitants of many places in the world are rarely related in a simple manner to the more ancient peoples of the same region.'” – from matt ridley.

Three hundred years of low non-paternity in a human population – “Here we use this approach to investigate 1273 conceptions over a period of 330 years in 23 families of the Afrikaner population in South Africa. We use haplotype frequency and diversity and coalescent simulations to show that the male population did not undergo a severe bottleneck and that paternity exclusion rates are high for this population. The rate of cuckoldry in this Western population was 0.9% (95% confidence interval 0.4–1.5%), and we argue that given the current data on historical populations we have to conclude that, at least for Western human populations, cuckoldry rate is probably in the range of 1%.” – h/t debbie kennett!